Anybody know if the input/output of the Vellios oil tank NPT fittings are 3/4" or 1"?

Thanks.

I'm looking at his old catalog and it says 914/6 Oil Tank with -12 AN Oil Line Connections.
Made from Vinyl Ester (will not rust) Part number OT02
It listed for $450.00 back in January 1991

not sure of the NPT thread size, but I know mine has AN-12 in and AN-16 out (with its adapters to the tank)... I know the outlet was very large.

3/4 pipe threads, same size as -12, you can get a -16 an to 3/4 pipe if so inclined..

The tank is indeed 3/4 NPT. However that does not equal its size - measuring the ID it comes out to .89" which is why I was so confused. Also while -12 AN is supposedly the same size - the ID of the NPT to AN fitting is actually a tad smaller on the AN side. Whereas the -16 AN is slightly bigger.

It was very frustrating to find out the size of the NPT - measuring does not give an accurate account because the actual size is bigger than it says!